title: luxS in bacteria isolated from 25- to 40-million-year-old amber.
abstract: Interspecies bacterial communication is mediated by autoinducer-2, whose synthesis depends on luxS. Due to the apparent universality of luxS (present in more than 40 bacterial species), it may have an ancient origin; however, no direct evidence is currently available. We amplified luxS in bacteria isolated from 25- to 40-million-year-old amber. The phylogenies and molecular clocks of luxS and the 16S rRNA gene from ancient and extant bacteria were determined as well. Luminescence assays using Vibrio harveyi BB170 aimed to determine the activity of luxS. While the phylogeny of luxS was very similar to that of extant Bacillus spp., amber isolates exhibited unique 16S rRNA gene phylogenies. This suggests that luxS may have been acquired by horizontal transfer millions of years ago. Molecular clocks of luxS suggest slow evolutionary rates, similar to those of the 16S rRNA gene and consistent with a conserved gene. Dendograms of the 16S rRNA gene and luxS show two separate clusters for the extant and ancient bacteria, confirming the uniqueness of the latter group.
authors.affiliation: Environmental Microbiology Laboratory, Department of Biology, University of Puerto Rico, Rico, San Juan, Puerto Rico; Department of Pathology, University of California, San Diego, CA, USA.
authors.forename: Tasha M
authors.initials: TM
authors.lastname: Santiago-Rodriguez
authors.forename: Ana R
authors.initials: AR
authors.lastname: Patrício
authors.forename: Jessica I
authors.initials: JI
authors.lastname: Rivera
authors.forename: Mariel
authors.initials: M
authors.lastname: Coradin
authors.forename: Alfredo
authors.initials: A
authors.lastname: Gonzalez
authors.forename: Gabriela
authors.initials: G
authors.lastname: Tirado
authors.forename: Raúl J
authors.initials: RJ
authors.lastname: Cano
authors.forename: Gary A
authors.initials: GA
authors.lastname: Toranzos
mesh_terms: D018647:Amber; D001419:Bacteria / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D013437:Carbon-Sulfur Lyases / Q000235:genetics* / Q000378:metabolism; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D008163:Luminescent Measurements; D010802:Phylogeny; D053038:Quorum Sensing; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014733:Vibrio / Q000201:enzymology / Q000235:genetics
chemical_list: D018647:Amber; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria
keywords: ancient bacteria; autoinducer-2; bacterial communication; luxS; quorum sensing